Growing complexity of storage infrastructure requires solutions for efficient use and management of resources. The use of a virtualized storage system enables to present to the user a logical space for data storage while the storage system itself handles the process of mapping it to the actual physical location. Today many virtualized storage systems implement thin provisioning. Thin provisioning is a method of optimizing the efficiency of utilization of available storage space in a storage system (including storage area network systems (SAN)). Thin provisioning operates by dynamically allocating disk space among users according to the actual space required by each user at any given time. Thin provisioning is different from the traditional model of “thick” or “fat” provisioning, which operates by allocating predefined storage spaces to users. In fat provisioning, storage spaces are often of a large size which is not adapted to the current needs of the user and thus, substantial parts of the allocated storage space often remain unused while the user is still required to pay for the unused space and its maintenance.
Zero page reclamation (ZPR) is a capability which is used with thin provisioning and enables to examine the content of data allocated to the physical storage and identify data portions of a predefined size, which contain only zeros. Such data portions can be unmapped from the physical storage while only their virtual representation is recorded. The physical storage can be thus freed and returned to the pool of available free storage space. In response to a request (e.g. to a read request) for a data portion containing only zeros, the data can be easily reconstructed. Accordingly, ZPR enables to further expand thin-provisioning and utilize disk storage space more efficiently.
Prior art references considered to be relevant as background to the invention are listed below. Acknowledgement of the references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the invention disclosed herein.
US20090089534 discloses a method for migrating data to a mass storage system, including receiving an incoming data partition for storage in the mass storage system and allocating logical storage for the incoming data partition in the mass storage system. The method further includes making a determination that the incoming data partition includes only zero data, and, in response to the determination, inhibiting physical storage of the incoming data partition in the mass storage system while maintaining the allocated logical storage for the incoming data partition.
There is still a need in the art to further improve the efficiency of the utilization of physical storage.